This page explains how Kai Zhang (USATT# 86637)'s rating went from 2667 to 2661 at the Westchester 2015 December Open held on 27 Dec 2015 - 28 Dec 2015. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.